I've never used any sort of 308 stripper clip before, but pulled out a 308 Pmag to check for the mounting slots that are cut into the back of the 5.56 mags for mounting the "spoon" only to find that there aren't any molded into the body of the 308 Pmag.

Are there any stripper-clip/spoons made that will work for loading a 308 Pmag?